Multiprocessing Queue Batch Get Up To Max N Elements

I need to get as many items as I can from a queue (up to N), in a blocking fashion. e.g: queue.get(16) Should return up to 16 elements, but block if empty.

Solution 1:

There's no such facility built in, so you'll need to code it yourself; for example,

import queue  # in Python 3; Queue in Python 2
...
defgetn(q, n):
    result = [q.get()]  # block until at least 1try:  # add more until `q` is empty or `n` items obtainedwhilelen(result) < n:
            result.append(q.get(block=False))
    except queue.Empty:
        passreturn result

Then do getn(queue, 16) for your conceptual queue.get(16).

Solution 2:

It waits 3 sec, if queue is empty. It returns last not full batch.

defget_batch_from_queue(q, batch_size):
    item_list = []

    try:
        for i inrange(batch_size):
            item_list.append(q.get(block=True, timeout=3))

        return item_list
    except queue.Empty:
        if(len(item_list)==0):
            returnNoneelse:
            return item_list

whileTrue:
    batch = get_batch_from_queue(q, batch_size=8)
    if batch == None:
        breakprint('len(batch)', len(batch))